Rewriting query technology using materialized view based on extended semantics

Aggregation queries with group-by is now a fundamental issue of data warehouse in ROLAP.Materialized views can significantly improve the performance of query.The paper makes an extension to general rewriting query using materialized views considering the hierarchical relation of attributes of dimension tables and discusses the restrict condition of rewriting query using single materialized view,then presents a method of rewriting query.In the final a local optimal search algorithm is described to find an approximately optimal rewriting query when we consider multi-view to rewrite query.The experimental result shows the algorithm proposed is more efficient.